
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>拖拽--Clone</title>
<style type="text/css">
body,div{margin:0;padding:0;}
body{background:#3e3e3e;}
div{position:absolute;width:100px;height:100px;cursor:move;border:1px solid #888;background:#000;}
#drag1{top:100px;left:100px;}
#drag2{top:100px;left:300px;}
#temp{opacity:0.3;filter:alpha(opacity=30);}
</style>
<script type="text/javascript">
var zIndex = 1;
window.onload = function ()
{
    var oDrag1 = document.getElementById("drag1");
    var oDrag2 = document.getElementById("drag2");
    drag(oDrag1);
    drag(oDrag2);
};
function drag(oDrag)
{
    var disX = dixY = 0;
    oDrag.onmousedown = function (event)
    {
        var event = event || window.event;
        disX = event.clientX - this.offsetLeft;
        disY = event.clientY - this.offsetTop;      
        
        var oTemp = document.createElement("div");
        oTemp["id"] = "temp";
        oTemp.style.left = this.currentStyle ? this.currentStyle["left"] : getComputedStyle(this, null)["left"];
        oTemp.style.top = this.currentStyle ? this.currentStyle["top"] : getComputedStyle(this, null)["top"];
        oTemp.style.zIndex = zIndex++;
        document.body.appendChild(oTemp);
        
        document.onmousemove = function (event)
        {
            var event = event || window.event;
            var iL = event.clientX - disX;
            var iT = event.clientY - disY;
            var maxL = document.documentElement.clientWidth - oDrag.offsetWidth;
            var maxT = document.documentElement.clientHeight - oDrag.offsetHeight
            
            iL <= 0 && (iL = 0);
            iT <= 0 && (iT = 0);
            iL >= maxL && (iL = maxL);
            iT >= maxT && (iT = maxT);
            
            oTemp.style.left = iL + "px";
            oTemp.style.top = iT + "px";
            return false;
        };
        
        document.onmouseup = function ()
        {
            document.onmousemove = null;
            document.onmouseup = null;
            oDrag.style.left = oTemp.style.left;
            oDrag.style.top = oTemp.style.top;
            oDrag.style.zIndex = oTemp.style.zIndex;
            document.body.removeChild(oTemp);
            oDrag.releaseCapture && oDrag.releaseCapture()
        };
        
        this.setCapture && this.setCapture();       
        return false;
    }   
}
</script>
</head>
<body>
<div id="drag1"></div>
<div id="drag2"></div>
</body>
</html>
